| // Copyright 2022 The Fuchsia Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include <unistd.h> |
| |
| #include <perftest/perftest.h> |
| |
| namespace { |
| |
| // Measure the time taken by getpid(). |
| // |
| // On Linux, this acts as a test to measure syscall overhead. getpid() is |
| // a good example of a very simple syscall. |
| // |
| // Note that glibc's getpid() wrapper function used to cache the process ID |
| // in user space, but that caching was removed in 2017, and the wrapper |
| // currently always does a syscall invocation. See: |
| // https://sourceware.org/glibc/wiki/Release/2.25#pid_cache_removal |
| bool Getpid() { |
| pid_t pid = getpid(); |
| perftest::DoNotOptimize(pid); |
| return true; |
| } |
| |
| void RegisterTests() { perftest::RegisterSimpleTest<Getpid>("Getpid"); } |
| PERFTEST_CTOR(RegisterTests) |
| |
| } // namespace |
